FROMLIST: [PATCH v6 05/12] arm: vdso: Add support for CLOCK_MONOTONIC_RAW

(cherry pick from url https://patchwork.kernel.org/patch/10052099/)

Take an effort to recode the arm64 vdso code from assembler to C
previously submitted by Andrew Pinski <apinski@cavium.com>, rework
it for use in both arm and arm64, overlapping any optimizations
for each architecture. But instead of landing it in arm64, land the
result into lib/vdso and unify both implementations to simplify
future maintenance.

Add a case for CLOCK_MONOTONIC_RAW to match up with support that
is available in arm64's vdso.

Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: James Morse <james.morse@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Andrew Pinski <apinski@cavium.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Bug: 63737556
Bug: 20045882
Change-Id: If9c09d131e236ba4a483dbc122e6b876f471df72
This commit is contained in:
Mark Salyzyn 2017-08-17 09:16:27 -07:00 committed by Timi
parent 73974dec71
commit d1fe361d48
3 changed files with 58 additions and 0 deletions

View file

@ -34,6 +34,11 @@ typedef u32 vdso_wtm_clock_nsec_t;
typedef u32 vdso_xtime_clock_sec_t;
#endif
#ifndef _VDSO_RAW_TIME_SEC_T
#define _VDSO_RAW_TIME_SEC_T
typedef u32 vdso_raw_time_sec_t;
#endif
/* Try to be cache-friendly on systems that don't implement the
* generic timer: fit the unconditionally updated fields in the first
* 32 bytes.
@ -58,6 +63,12 @@ struct vdso_data {
u64 xtime_clock_snsec; /* CLOCK_REALTIME sub-ns base */
u32 tz_minuteswest; /* timezone info for gettimeofday(2) */
u32 tz_dsttime;
/* Raw clocksource multipler */
u32 cs_raw_mult;
/* Raw time */
vdso_raw_time_sec_t raw_time_sec;
u32 raw_time_nsec;
};
union vdso_data_store {

View file

@ -319,9 +319,12 @@ void update_vsyscall(struct timekeeper *tk)
if (!vdso_data->use_syscall) {
vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
vdso_data->raw_time_sec = tk->raw_sec;
vdso_data->raw_time_nsec = tk->tkr_raw.xtime_nsec;
vdso_data->xtime_clock_sec = tk->xtime_sec;
vdso_data->xtime_clock_snsec = tk->tkr_mono.xtime_nsec;
vdso_data->cs_mono_mult = tk->tkr_mono.mult;
vdso_data->cs_raw_mult = tk->tkr_raw.mult;
/* tkr_mono.shift == tkr_raw.shift */
vdso_data->cs_shift = tk->tkr_mono.shift;
vdso_data->cs_mask = tk->tkr_mono.mask;

View file

@ -194,6 +194,40 @@ static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts)
return 0;
}
static notrace int do_monotonic_raw(const struct vdso_data *vd,
struct timespec *ts)
{
u32 seq, mult, shift;
u64 nsec, cycle_last;
u64 mask;
vdso_raw_time_sec_t sec;
do {
seq = vdso_read_begin(vd);
if (vd->use_syscall)
return -1;
cycle_last = vd->cs_cycle_last;
mult = vd->cs_raw_mult;
shift = vd->cs_shift;
mask = vd->cs_mask;
sec = vd->raw_time_sec;
nsec = vd->raw_time_nsec;
} while (unlikely(vdso_read_retry(vd, seq)));
nsec += get_clock_shifted_nsec(cycle_last, mult, mask);
nsec >>= shift;
/* open coding timespec_add_ns to save a ts->tv_nsec = 0 */
ts->tv_sec = sec + __iter_div_u64_rem(nsec, NSEC_PER_SEC, &nsec);
ts->tv_nsec = nsec;
return 0;
}
#else /* CONFIG_ARM_ARCH_TIMER */
static notrace int do_realtime(const struct vdso_data *vd, struct timespec *ts)
@ -206,6 +240,12 @@ static notrace int do_monotonic(const struct vdso_data *vd, struct timespec *ts)
return -1;
}
static notrace int do_monotonic_raw(const struct vdso_data *vd,
struct timespec *ts)
{
return -1;
}
#endif /* CONFIG_ARM_ARCH_TIMER */
notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
@ -227,6 +267,10 @@ notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
if (do_monotonic(vd, ts))
goto fallback;
break;
case CLOCK_MONOTONIC_RAW:
if (do_monotonic_raw(vd, ts))
goto fallback;
break;
default:
goto fallback;
}